resource_request_policy.cc revision 7dbb3d5cf0c15f500944d211057644d6a2f37371 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "chrome/renderer/extensions/resource_request_policy.h"
6
7#include "base/command_line.h"
8#include "base/logging.h"
9#include "base/strings/stringprintf.h"
10#include "chrome/common/chrome_switches.h"
11#include "chrome/common/extensions/extension.h"
12#include "chrome/common/extensions/extension_set.h"
13#include "chrome/common/extensions/manifest_handlers/icons_handler.h"
14#include "chrome/common/extensions/manifest_url_handler.h"
15#include "chrome/common/extensions/web_accessible_resources_handler.h"
16#include "chrome/common/url_constants.h"
17#include "content/public/common/page_transition_types.h"
18#include "extensions/common/constants.h"
19#include "third_party/WebKit/public/platform/WebString.h"
20#include "third_party/WebKit/public/web/WebConsoleMessage.h"
21#include "third_party/WebKit/public/web/WebDocument.h"
22#include "third_party/WebKit/public/web/WebFrame.h"
23#include "url/gurl.h"
24
25namespace extensions {
26
27// This method does a security check whether chrome-extension:// URLs can be
28// requested by the renderer. Since this is in an untrusted process, the browser
29// has a similar check to enforce the policy, in case this process is exploited.
30// If you are changing this function, ensure equivalent checks are added to
31// extension_protocols.cc's AllowExtensionResourceLoad.
32
33// static
34bool ResourceRequestPolicy::CanRequestResource(
35    const GURL& resource_url,
36    WebKit::WebFrame* frame,
37    content::PageTransition transition_type,
38    const ExtensionSet* loaded_extensions) {
39  CHECK(resource_url.SchemeIs(extensions::kExtensionScheme));
40
41  const Extension* extension =
42      loaded_extensions->GetExtensionOrAppByURL(ExtensionURLInfo(resource_url));
43  if (!extension) {
44    // Allow the load in the case of a non-existent extension. We'll just get a
45    // 404 from the browser process.
46    return true;
47  }
48
49  // Disallow loading of packaged resources for hosted apps. We don't allow
50  // hybrid hosted/packaged apps. The one exception is access to icons, since
51  // some extensions want to be able to do things like create their own
52  // launchers.
53  std::string resource_root_relative_path =
54      resource_url.path().empty() ? std::string()
55                                  : resource_url.path().substr(1);
56  if (extension->is_hosted_app() &&
57      !IconsInfo::GetIcons(extension)
58          .ContainsPath(resource_root_relative_path)) {
59    LOG(ERROR) << "Denying load of " << resource_url.spec() << " from "
60               << "hosted app.";
61    return false;
62  }
63
64  // Disallow loading of extension resources which are not explicitly listed
65  // as web accessible if the manifest version is 2 or greater.
66  if (!WebAccessibleResourcesInfo::IsResourceWebAccessible(
67          extension, resource_url.path()) &&
68      !CommandLine::ForCurrentProcess()->HasSwitch(
69          switches::kDisableExtensionsResourceWhitelist)) {
70    GURL frame_url = frame->document().url();
71    GURL page_url = frame->top()->document().url();
72
73    // Exceptions are:
74    // - empty origin (needed for some edge cases when we have empty origins)
75    bool is_empty_origin = frame_url.is_empty();
76    // - extensions requesting their own resources (frame_url check is for
77    //     images, page_url check is for iframes)
78    bool is_own_resource = frame_url.GetOrigin() == extension->url() ||
79        page_url.GetOrigin() == extension->url();
80    // - devtools (chrome-extension:// URLs are loaded into frames of devtools
81    //     to support the devtools extension APIs)
82    bool is_dev_tools = page_url.SchemeIs(chrome::kChromeDevToolsScheme) &&
83                        !ManifestURL::GetDevToolsPage(extension).is_empty();
84    bool transition_allowed =
85        !content::PageTransitionIsWebTriggerable(transition_type);
86    // - unreachable web page error page (to allow showing the icon of the
87    //   unreachable app on this page)
88    bool is_error_page = frame_url == GURL(content::kUnreachableWebDataURL);
89
90    if (!is_empty_origin && !is_own_resource &&
91        !is_dev_tools && !transition_allowed && !is_error_page) {
92      std::string message = base::StringPrintf(
93          "Denying load of %s. Resources must be listed in the "
94          "web_accessible_resources manifest key in order to be loaded by "
95          "pages outside the extension.",
96          resource_url.spec().c_str());
97      frame->addMessageToConsole(
98          WebKit::WebConsoleMessage(WebKit::WebConsoleMessage::LevelError,
99                                    WebKit::WebString::fromUTF8(message)));
100      return false;
101    }
102  }
103
104  return true;
105}
106
107// static
108bool ResourceRequestPolicy::CanRequestExtensionResourceScheme(
109    const GURL& resource_url,
110    WebKit::WebFrame* frame) {
111  CHECK(resource_url.SchemeIs(chrome::kExtensionResourceScheme));
112
113  GURL frame_url = frame->document().url();
114  if (!frame_url.is_empty() &&
115      !frame_url.SchemeIs(extensions::kExtensionScheme)) {
116    std::string message = base::StringPrintf(
117        "Denying load of %s. chrome-extension-resources:// can only be "
118        "loaded from extensions.",
119      resource_url.spec().c_str());
120    frame->addMessageToConsole(
121        WebKit::WebConsoleMessage(WebKit::WebConsoleMessage::LevelError,
122                                  WebKit::WebString::fromUTF8(message)));
123    return false;
124  }
125
126  return true;
127}
128
129ResourceRequestPolicy::ResourceRequestPolicy() {
130}
131
132}  // namespace extensions
133